Field of the Invention
This invention relates generally to tire treads, and more particularly, to tire treads having sipes, where at least a portion of the sipe has a reduced thickness.
Description of the Related Art
Tire treads are known to include a pattern of voids and/or discontinuities such arranged along a ground-engaging side of the tread to provide sufficient traction and handling during particular conditions. For example, grooves provide voids into which water, mud, or other environmental materials may be diverted to better allow the tread surface to engage a ground surface. By providing the pattern of voids/discontinuities, tread elements are formed along the tread, where the outer portion of said elements are arranged along the outer side of the tread to provide traction as the outer side engages the ground surface (that is, a surface upon with the tire operates, which is also referred to herein as a tire operating surface).
It is well known that the tire tread wears during tire operation due to the generation of slip between the outer side of the tread and the tire operating surface. This not only occurs when the rolling direction of the tire is biased relative to the direction of vehicle travel to generate lateral traction forces, such as when a vehicle is changing direction during turning or cornering maneuvers, but also when the vehicle is traveling in a straight line.
In certain instances, it is advantageous to employ sipes, which are narrow voids or slits that generally close at some instance within a tire footprint, which is the area of contact between the tire and the tire operating surface. For example, sipes can offer benefits in traction, such as in snow. Sipes, however, can reduce the stiffness of a tire tread, resulting in undesired tread wear. Therefore, there is a need to increase tread stiffness by reducing the thickness of sipes, which in turn will reduce the occurrence of wear when employing the use of sipes in tire treads.